Balancing the Tradeoff between Profit and Fairness in Rideshare Platforms During High-Demand Hours

Rideshare platforms, when assigning requests to drivers, tend to maximize profit for the system and/or minimize waiting time for riders. Such platforms can exacerbate biases that drivers may have over certain types of requests. We consider the case of peak hours when the demand for rides is more than the supply of drivers. Drivers are well aware of their advantage during the peak hours and can choose to be selective about which rides to accept. Moreover, if in such a scenario, the assignment of requests to drivers (by the platform) is made only to maximize profit and/or minimize wait time for riders, requests of a certain type (e.g. from a non-popular pickup location, or to a non-popular drop-off location) might never be assigned to a driver. Such a system can be highly unfair to riders. However, increasing fairness might come at a cost of the overall profit made by the rideshare platform. To balance these conflicting goals, we present a flexible, non-adaptive algorithm, \lpalg, that allows the platform designer to control the profit and fairness of the system via parameters $\alpha$ and $\beta$ respectively. We model the matching problem as an online bipartite matching where the set of drivers is offline and requests arrive online. Upon the arrival of a request, we use \lpalg to assign it to a driver (the driver might then choose to accept or reject it) or reject the request. We formalize the measures of profit and fairness in our setting and show that by using \lpalg, the competitive ratios for profit and fairness measures would be no worse than $\alpha/e$ and $\beta/e$ respectively. Extensive experimental results on both real-world and synthetic datasets confirm the validity of our theoretical lower bounds. Additionally, they show that \lpalg under some choice of $(\alpha, \beta)$ can beat two natural heuristics, Greedy and Uniform, on \emph{both} fairness and profit

Nothing But The Truth And The Whole Truthiness: Examining Markers Of Authenticity In The Modern Documentary

This thesis examines the phenomenon comedian Stephen Colbert dubbed “truthiness” as it pertains to representations of authenticity in the documentary film genre. This thesis identifies several “markers of authenticity,” such as voice-over narration and confessional interviews, which have come to represent trustworthy representations of reality in the documentary form. This thesis also provides a content analysis of the markers’ use in five carefully selected contemporary documentaries, including Super Size Me (Spurlock, 2004) and Bowling for Columbine (Moore, 2002). The purpose of the study is to create a more comprehensive definition of the word truthiness as it pertains to the documentary film genre. The results of the study show that truthiness exists when a marker of authenticity is used to support the articulation of the documentarian’s viewpoint at the expense of a subject’s authenticity. The results of the study also show that truthiness exists when any marker of authenticity is used to convey a secondary meaning for comedic or ironic effect

Arctic Profiles: Second Series

In the June 1982 issue of Arctic, Richard Davis introduced "Arctic Profiles." At the time he said the purpose of the series was to cover "a more subjective and human element that has influenced the history of arctic development." He continued, "Should this series prove successful ..." more could follow. ... Because of the success of the Profiles, Arctic has decided to maintain the series and has asked us to see it through a second phase. ... The second series of profiles will be more contemporary but continue to recognize the contribution of those no longer active or alive. ..

Use of Dynamic Visualizations for Engineering Technology, Industrial Technology, and Science Education Students: Implications on Ability to Correctly Create a Sectional View Sketch

Spatial abilities, specifically visualization, play a significant role in the achievement in a wide array of professions including, but not limited to, engineering, technical, mathematical, and scientific professions. However, there is little correlation between the advantages of spatial ability as measured through the creation of a sectional-view sketch between engineering technology, industrial technology, and science education students. A causal-comparative study was selected as a means to perform the comparative analysis of spatial visualization ability. This study was done to determine the existence of statistically significant difference between engineering technology, industrial technology, and science education students’ ability to correctly create a sectional-view sketch of the presented object. No difference was found among the sketching abilities of students who had an engineering technology, industrial technology, or science education background. The results of the study have revealed some interesting results. © 2016, Virginia Polytechnic Institute. All rights reserved

Heat conductivity of DNA double helix

Thermal conductivity of isolated single molecule DNA fragments is of importance for nanotechnology, but has not yet been measured experimentally. Theoretical estimates based on simplified (1D) models predict anomalously high thermal conductivity. To investigate thermal properties of single molecule DNA we have developed a 3D coarse-grained (CG) model that retains the realism of the full all-atom description, but is significantly more efficient. Within the proposed model each nucleotide is represented by 6 particles or grains; the grains interact via effective potentials inferred from classical molecular dynamics (MD) trajectories based on a well-established all-atom potential function. Comparisons of 10 ns long MD trajectories between the CG and the corresponding all-atom model show similar root-mean-square deviations from the canonical B-form DNA, and similar structural fluctuations. At the same time, the CG model is 10 to 100 times faster depending on the length of the DNA fragment in the simulation. Analysis of dispersion curves derived from the CG model yields longitudinal sound velocity and torsional stiffness in close agreement with existing experiments. The computational efficiency of the CG model makes it possible to calculate thermal conductivity of a single DNA molecule not yet available experimentally. For a uniform (polyG-polyC) DNA, the estimated conductivity coefficient is 0.3 W/mK which is half the value of thermal conductivity for water. This result is in stark contrast with estimates of thermal conductivity for simplified, effectively 1D chains ("beads on a spring") that predict anomalous (infinite) thermal conductivity. Thus, full 3D character of DNA double-helix retained in the proposed model appears to be essential for describing its thermal properties at a single molecule level.Comment: 16 pages, 12 figure

A Preliminary Investigation of the Cr3Si-Mo Pseudo-Binary Phase Diagram

An investigation was undertaken to study the phase relations in Cr3Si alloyed with Mo varying from 10 to 83.5 wt. % of the material. Specimens were prepared from arc-melted buttons that were subsequently heat treated at 1673 K for 200 h and air quenched to room temperature to structures. Alloys containing more than 20 wt. % MO were primarily two-phase materials of M3Si and M5Si3, where M is (Cr,Mo). Three alloys contained less than 5% of a third phase, which also had the M5Si3 crystal structure. Differential thermal analysis (DTA) was performed on several specimens at temperatures up to 2073 K in order to determine a solidus curve for the M3Si phase. Since only one DTA peak was observed in each alloy, the M5Si3 phase must melt above 2073 K, the maximum temperature examined. A preliminary pseudo-binary phase diagram for (Cr,Mo)3Si and a portion of the 1673 K isothermal section of the Cr-Mo-Si ternary phase diagram are presented